Serum Uric Acid Revealed a U-Shaped Relationship With All-Cause Mortality and Cardiovascular Mortality in High Atherosclerosis Risk Patients: The ASSURE Study

The impact of uric acid on acute coronary syndrome prognosis in elderly patients

BACKGROUND

Uric acid (UA) plays an important role in cardiovascular diseases, yet its implications in elderly patients remains incompletely understood. This study aimed to explore the impact of UA on the prognosis in advanced-age patients with acute coronary syndrome (ACS).

METHODS

We included 526 patients aged 80 and older who were diagnosed with ACS. The UA levels were measured at admission, and patients were divided into four groups based on quartiles of UA levels. Major adverse cardiovascular events (MACE) during follow-up were recorded.

RESULTS

The median UA level was 344.09 μmol/L, while the median follow-up duration was 64 months. Kaplan-Meier curves demonstrated a higher cumulative incidence of MACE during long-term follow-up in the Q4 group (Log-rank p < 0.05). Cox regression analysis revealed an independent correlation between UA levels and an increased risk of MACE (HR 1.002, 95%CI 1.000-1.003, p = 0.021). The ROC curve indicated that the optimal UA value for predicting MACE was 324.25 μmol/L. After matching through PSM, the MACE-free survival rate was lower in both hyperuricemia group (UA> 420.00 μmol/L) and high UA group (324.25 μmol/L < UA≤ 420.00 μmol/L) compared to the control group. Both hyperuricemia and high UA levels were independent risk factors for long-term MACE in advanced-age ACS patients, with HR values of 1.546 (1.049-2.280, p = 0.028) and 1.491 (1.011-2.198, p = 0.044), respectively.

CONCLUSION

Elevated UA levels were identified as independent risk factors for MACE in elderly patients with ACS. The optimal predictive value of UA for poor cardiovascular prognosis was significantly lower than the traditional definition of hyperuricemia.

Predictive value of uric acid to albumin ratio for carotid atherosclerosis in type 2 diabetes mellitus: A retrospective study

BACKGROUND

This study aims to evaluate the correlation between the uric acid (UA) to albumin (ALB) ratio (UAR) and carotid atherosclerosis (CAS) in patients with type 2 diabetes mellitus (T2DM), as well as to assess the predictive value of UAR for CAS.

METHODS

A cross-sectional, single-center study was conducted, retrospectively analyzing hematological parameters from 259 T2DM patients with CAS (T2DM-CAS) and 131 T2DM patients without CAS (T2DM-WCAS). Carotid intima-media thickness (IMT) and carotid plaques (CAP) were measured using Doppler ultrasound.

RESULTS

The UAR level in the T2DM-CAS group was significantly higher than that in the T2DM-WCAS group (P <  0.001). Multivariate logistic regression analysis revealed that UAR is an independent risk factor for T2DM-CAS (P <  0.001). The area under the ROC curve (AUC) for UAR in predicting T2DM-CAS was 0.712, with a Youden index of 0.278.

CONCLUSION

High levels of UAR are closely associated with the occurrence of T2DM-CAS and may serve as a useful biomarker for predicting T2DM-CAS.

Gout and Hyperuricemia: A Narrative Review of Their Comorbidities and Clinical Implications

Gout is the most common form of inflammatory arthritis, caused by the deposition of monosodium urate crystals in the joints due to elevated serum uric acid levels. Its prevalence and associated healthcare burden have been rising in recent decades, a trend expected to continue. It is crucial to recognize that gout and hyperuricemia are not merely causes of painful joint flares, but systemic metabolic disorders linked to a broad spectrum of comorbidities such as cardiovascular diseases, chronic kidney disease, diabetes, insulin resistance, steatotic liver disease, osteoarthritis, and respiratory and eye diseases. Numerous risk factors for gout and hyperuricemia have been identified, with recent research uncovering further associations with other conditions. To optimize patient outcomes, gout and hyperuricemia must be addressed through a holistic approach that accounts for these risk factors while providing comprehensive management of related comorbidities affecting various organ systems. This review summarizes the current knowledge on the risk factors, comorbidities, and clinical implications of gout and hyperuricemia. Future research should focus on improving patient outcomes by tailoring treatments individually and addressing the underlying metabolic comorbidities of gout with multimodal treatment.

Association between serum uric acid and prediabetes in a normal Chinese population: A cross-sectional study

Cardiovascular events are frequent among individuals with prediabetes. And the relationship between cardiovascular diseases and elevated serum uric acid (SUA) levels has been supported by extensive scientific evidence. However, there remains controversy regarding the correlation between elevated SUA and prediabetes. The aim of this study was to investigate the association between elevated SUA levels and the prevalence of prediabetes and gender differences in the association. A total of 190,891 individuals who participated in health checkups at the Health Promotion Center of Sir Run Run Shaw Hospital of Zhejiang University from January 2017 to December 2021 were included in this cross-sectional study. The health checkups were carried out by trained general practitioners and nurses. The diagnostic criteria for diabetes and prediabetes are defined in the Standards of Medical Care in Diabetes-2022. The association between SUA levels and diabetes and prediabetes was examined based on logistic regression analysis. The dose-response effect between SUA levels and diabetes and prediabetes in both sexes was assessed using a restricted cubic spline (RCS) regression model. Among 190,891 participants, this study included 106,482 males (55.8%) and 84,409 females (44.2%). There were 46,240 (24.2%) patients with prediabetes and 20,792 (10.9%) patients with diabetes. SUA was divided into quartiles (Q). Compared to the SUA Q1 group, the prevalence of prediabetes was elevated in the SUA Q4 group (OR = 1.378, 95% CI = 1.321-1.437), but diabetes risk was decreased in the SUA Q4 group (OR = 0.690, 95% CI = 0.651-0.730). We found that SUA levels were correlated with prediabetes more significantly in male subjects (OR = 1.328, 95% CI = 1.272-1.386) than in female subjects (OR = 1.184, 95% CI = 1.122-1.249) (P for interaction < .001). Higher SUA levels were strongly related to an elevated prevalence of prediabetes but a decreased prevalence of diabetes. The association of SUA in prediabetes was more significant in men.

Sex-specific associations between prolonged serum uric acid levels and risk of major adverse cardiovascular events

Background

While hyperuricemia has been correlated with cardiovascular (CV) diseases, further evidence is required to evaluate the implications of stable serum uric acid (sUA) levels, especially concerning low sUA. This study aimed to investigate prolonged stable sUA levels and CV events/mortality.

Methods

We conducted a retrospective cohort study at a medical center using electronic medical records linked with the national claims database. Patients with at least two sUA measurements, with intervals ranging from 6 months to 4 years, were included. The mean of the first two eligible sUA measurements were analyzed, stratified by sex. Outcomes of interest comprised major adverse cardiovascular events (MACE), heart failure hospitalization, CV and all-cause mortality.

Results

This study included 33,096 patients (follow-up: men 6.6 years, women 6.4 years). After multivariable adjustment, cubic spline models showed that long-term high sUA levels were consistently associated with a higher risk of MACE, heart failure hospitalization, CV and all-cause mortality. A U-shaped association was observed between sUA levels and all-cause mortality in both sexes and between sUA levels and CV mortality in women. The impact of sUA, especially lower levels, on CV events and mortality was more pronounced in women than in men.

Conclusion

Long-term high sUA levels are consistently associated with increased risk of CV events and mortality. A U-shaped association between sUA levels and all-cause mortality was observed in both men and women and was pronounced in women. The findings underscore the importance of considering sUA levels, especially in women, when assessing CV risk.

Consumption of Total and Specific Alcoholic Beverages and Long-Term Risk of Gout Among Men and Women

Importance

Previous studies on alcohol consumption and incident gout have mostly included men or combined both sexes, and the sex-specific associations between alcohol consumption and gout are poorly understood.

Objective

To evaluate the consumption of total and specific alcoholic beverages in association with incident gout in men and women.

Design, Setting, and Participants

This prospective cohort study included 401 128 participants in the UK Biobank aged 37 to 73 years who were free of gout at baseline (2006-2010). Participants were followed up through December 31, 2021, and data were analyzed between August 2023 and June 2024.

Exposure

Questionnaire-based consumption of total alcohol and specific alcoholic beverages.

Main Outcomes and Measures

The outcome was incident gout, identified using hospital records. Multivariable Cox proportional hazards regression models were used to estimate sex-specific hazard ratios (HRs) and 95% CIs of incident gout associated with alcohol consumption, with a particular consideration of reverse causation bias.

Results

The main analysis included 179 828 men (mean [SD] age, 56.0 [8.2] years) and 221 300 women (mean [SD] age, 56.0 [8.0] years). Current drinkers showed a higher risk of gout than never drinkers among men (HR, 1.69; 95% CI, 1.30-2.18) but not among women (HR, 0.83; 95% CI, 0.67-1.03). Among current drinkers, higher total alcohol consumption was associated with a higher risk of gout among both sexes and more strongly among men than women (men: HR, 2.05 [95% CI, 1.84-2.30]; women: HR, 1.34 [95% CI, 1.12-1.61]). The most evident sex difference in the consumption of specific alcoholic beverages was observed for beer or cider (men: mean [SD], 4.2 [4.8] pints per week; women: mean [SD], 0.4 [1.1] pints per week). Consumption of champagne or white wine, beer or cider, and spirits each was associated with a higher risk of gout among both sexes, with beer or cider showing the strongest association per 1 pint per day (men: HR, 1.60 [95% CI, 1.53-1.67]; women: HR, 1.62 [95% CI, 1.02-2.57]). Some inverse associations between light to moderate consumption of specific alcoholic beverages and gout were eliminated after adjusting for other alcoholic beverages and excluding individuals who had reduced alcohol consumption for health reasons, self-reported poor health, or had cardiovascular disease, cancer, or kidney failure at baseline, or developed gout within the first 2 years of follow-up.

Conclusions and Relevance

In this cohort study, higher consumption of several specific alcoholic beverages was associated with a higher risk of gout among both sexes. The sex-specific associations for total alcohol consumption may be associated with differences between men and women in the types of alcohol consumed.

Hyperuricaemia-associated all-cause mortality risk effect is increased by non-impaired kidney function - Is renal hyperuricaemia less dangerous?

BACKGROUND

Both hyperuricaemia and chronic kidney disease are known mortality risk factors. This study examined the modifying effect of renal function on hyperuricaemia-associated mortality risk, which is an issue that has not been studied before.

METHODS

Data on levels of serum uric acid (SUA), creatinine, cystatin C and other variables of persons aged 52-76 years were collected. Persons with SUA >410 μmol/L (75th percentile) were classified as clearly hyperuricaemic and persons with eGFR of ≤67 ml/min (25th percentile) as having reduced kidney function.

RESULTS

Reduced kidney function was associated with higher mortality in both SUA groups. When compared to individuals with SUA ≤410 μmol/L and eGFR >67 ml/min the hazard ratio (HR) for all-cause mortality was 1.53 (95 % CI: 1.26-1.84) in clearly hyperuricaemic persons with reduced kidney function, 1.26 (95 % CI: 1.02-1.55) in clearly hyperuricaemic persons with eGFR of >67 ml/min and 1.15 (95 % CI: 0.96-1.39) in persons with SUA ≤410 μmol/L and reduced kidney function. The HR for hyperuricaemia-related premature death was lowest in individuals with reduced eGFR, and it rose strikingly as the eGFR increased above 90 ml/min.

CONCLUSIONS

Reduced kidney function is a risk factor for mortality both in individuals with normal and elevated SUA. The hyperuricaemia-associated mortality risk is remarkably higher in individuals with normal kidney function than in individuals with reduced kidney function. Presumably overproduction of uric acid (metabolic hyperuricaemia) is a separate and more deleterious entity than hyperuricaemia resulting from reduced renal excretion of uric acid (renal hyperuricaemia).

Association between hyperuricemia and long-term mortality in patients with hypertension: results from the NHANES 2001-2018

Objective

The prevalence of hyperuricemia and hypertension is steadily increasing, and these conditions often share common risk factors. This study aimed to investigate the association among hyperuricemia, hypertension, and all-cause mortality in a nationally representative U.S. population.

Methods

Data for 38,644 participants were obtained from the National Health and Nutrition Examination Survey (NHANES) 2001-2018. Hyperuricemia was defined as a serum urate concentration >420 μmol/L in men and >360 μmol/L in women. Information regarding death outcomes was obtained through the National Death Index (NDI). Multivariate logistic regression, Cox proportional hazards models, and restricted cubic spline (RCS) analyses were used to evaluate the association between hyperuricemia and hypertension in all included participants, as well as long-term mortality in patients with hypertension.

Results

Among all participants, 6,956 (18.0%) had hyperuricemia, while 31,688 (82.0%) had nonhyperuricemia. According to the adjusted models, hyperuricemia was more strongly associated with hypertension (OR 2.04) than was non-hyperuricemia. During the median follow-up period of 78 months, both hyperuricemia (HR 1.48, 1.95) and hypertension (HR 1.42, 1.69) independently associated with the increased risk of all-cause mortality and cardiovascular mortality, respectively, with the highest risk observed in those with both conditions (HR 1.87, 2.82). RCS analyses revealed nonlinear J-shaped (for hypertension) and U-shaped (for both all-cause and cardiovascular mortality) relationships with serum urate levels.

Conclusions

Hyperuricemia is associated with an elevated risk of developing hypertension compared to non-hyperuricemia. Among patients with hypertension, those with hyperuricemia are more likely to experience all-cause and cardiovascular mortality during long-term follow-up.

Novel pathological implications of serum uric acid with cardiovascular disease risk in obesity

AIMS

This cohort study intended to elucidate the association between serum uric acid (SUA) levels and cardiovascular disease events in Japanese patients with obesity.

METHODS

Altogether, 450 obese Japanese outpatients were enrolled in a multicenter prospective cohort Japan, the Japan Obesity and Metabolic Syndrome Study. Primary analysis regarding the measurements of cardiovascular risk factors, including SUA levels, and the occurrence of macrovascular complications was based on following the participants over a 5-year period.

RESULTS

Of the eligible patients, 335 (74.4%) were followed into the fifth year. During the study period, 15 coronary heart disease, 7 stroke, and 6 arteriosclerosis obliterans events occurred in 39 patients. The CVD incidence rate was 15.8 per 1000 person-years. In the analysis of adjusted models for traditional risk factors, hyperuricemia was a significant factor for the incidence of CVD events, especially in female obese patients. Additionally, we estimated the association between SUA levels and CVD events using cubic spline models, which showed a U-shaped association in both male and female patients.

CONCLUSIONS

SUA is an effective predictor of CVD events in female obese patients and a risk factor for CVD incident in obese patients.

Hyperuricemia and coronary heart disease: The mediating role of blood pressure and thrombospondin 3

BACKGROUND & AIMS

Although hyperuricemia is a known risk factor for coronary heart disease (CHD), little is known about the role of blood pressure in mediating this association. The purpose of this study is to investigate the role of blood pressure-related indicators and Thrombospondin 3 (THBS3) in the association between hyperuricemia and CHD.

METHODS AND RESULTS

Our observational epidemiology study included 593 CHD cases and 760 controls from a residential stable sample. We also chose 43 new CHD patients and 43 controls to test the expression levels of THBS3 using ELISA kits. We used logistic regression models and mediating effect analysis to investigate the relationships between hyperuricemia and CHD, as well as the mediating role of blood pressure-related indicators and THBS3. In the general population (OR: 2.001 [95% CI: 1.528-2.622]), male population (OR: 1.591 [95% CI: 1.119-2.262]), and female population (OR: 2.813 [95% CI: 1.836-4.310]), hyperuricemia is an independent risk factor for CHD. In general, average systolic blood pressure (SBP) and average pulse pressure difference (PPD) mediated 3.35% and 4.59%, respectively, of the association between hyperuricemia and CHD, and 6.60% and 6.60% in women. However, in the male population, we have not yet found that blood pressure-related indicators had a significant mediating effect. Meanwhile, we found that THBS3 mediated 19.23% of the association between hyperuricemia and CHD.

CONCLUSIONS

Average SBP, PPD, and THBS3 all play a role in the association of hyperuricemia and CHD. In the female population, similar mediating results in blood pressure-related indicators were observed.

High Uric Acid Promotes Atherosclerotic Plaque Instability by Apoptosis Targeted Autophagy

AIMS

Acute rupture or erosion of unstable atherosclerotic plaques is a major cause of adverse consequences of atherosclerotic cardiovascular disease, often leading to myocardial infarction or stroke. High uric acid (HUA) is associated with the increasing risk of cardiovascular events and death. However, the mechanism by which HUA promotes atherosclerosis and whether HUA affects plaque stability are still unclear.

METHODS

We constructed an atherosclerotic Apoe-/- mouse model with HUA. The progression of atherosclerosis and plaques was determined by Oil Red O staining, hematoxylin and eosin (H&E) staining, and Masson staining. TdT-mediated dUTP nick-end labeling assay and immunohistochemistry were used to observe the changes of apoptosis and autophagy in plaques, respectively. Then, we validated the in vivo results with RAW 264.7 cell line.

RESULTS

HUA promoted atherosclerosis and exacerbated plaque vulnerability, including significantly increased macrophage infiltration, lipid accumulation, enlarged necrotic cores, and decreased collagen fibers. HUA increased cell apoptosis and inhibited autophagy in plaques. In vitro results showed that HUA decreased cell viability and increased cell apoptosis in foam cells macrophages treated with oxidized low-density lipoprotein. An activator of autophagy, rapamycin, can partially reverse the increasing apoptosis.

CONCLUSION

HUA promoted atherosclerosis and exacerbated plaque vulnerability, and HUA facilitates foam cell apoptosis by inhibiting autophagy.

Association between serum uric acid levels and peripheral artery disease in Chinese adults with hypertension

Background

Higher serum uric acid (SUA) can cause gout, which is principally characterized by arthritis due to monosodium urate crystal deposition in the lower extremities. High levels of SUA have been linked to endothelial dysfunction, oxidative stress, and inflammation, all of which are involved in the pathogenesis of peripheral artery disease(PAD). To date, the relationship between SUA levels and PAD is still poorly understood.

Method

An analysis of 9,839 Chinese adults with essential hypertension from the ongoing China H-type Hypertension Registry Study was conducted in this cross-sectional study. Patients with an ABI ≤0.9 was diagnosed with PAD. Hyperuricemia was defined as SUA levels >420 mol/L in men and >360 mol/L in women. The association between SUA levels and PAD was evaluated using multivariable logistic regression models based on odds ratios (ORs) and their 95% confidence intervals (CIs).

Results

The enrolled subjects ranged in age from 27 to 93 years, with a mean age of 63.14 ± 8.99 years. The proportion of male patients was 46.22%, and the prevalence of hyperuricemia was 50.72%. In males, hyperuricemia was positively associated with the risk of PAD (adjusted OR per SD increase: 1.72, 95% CI 1.17 to 2.53, P =0.006). Males in the highest SUA tertile were significantly more likely to have PAD (adjusted OR: 2.63, 95% CI 1.42 to 4.86, P = 0.002; P for trend = 0.001). However, this positive relationship was not observed in females (adjusted OR: 1.29, 95% CI 0.77 to 2.17, P = 0.327; P for trend = 0.347).

Conclusion

According to this cross-sectional study, higher SUA levels were positively associated with PAD in male hypertensive patients, while this positive relationship disappeared in female participants.

Hyperuricaemia: prevalence and association with mortality in an elderly Finnish population

OBJECTIVE

To establish the prevalence of hyperuricaemia in an elderly Finnish cohort and to assess its association with comorbidities and mortality.

DESIGN

Prospective cohort study.

SETTING

Good Ageing in Lahti Region study, Finland 2002-2012 (mortality data analysed until 2018).

PARTICIPANTS

2673 participants (mean age 64 years; 47% men).

PRIMARY AND SECONDARY OUTCOME MEASURES

Prevalence of hyperuricaemia in the study population was detected. Associations between hyperuricaemia and mortality were assessed using multivariable adjusted Cox proportional hazards models.

METHODS

Data from a prospective, population-based study of elderly people (52-76 years) in the Lahti region, Finland, were used. Information on serum uric acid (SUA) levels as well as several other laboratory variables, comorbidities, lifestyle habits and socioeconomic factors was collected, and the association between SUA level and mortality in a 15-year follow-up period was analysed.

RESULTS

Of 2673 elderly Finnish persons included in the study 1197 (48%) were hyperuricaemic. Hyperuricaemia was extremely prevalent in men (60%). There was an association between elevated SUA and mortality which remained after adjustment for potential confounding factors (age, gender, education, smoking status, body mass index, hypertension and dyslipidaemia). The adjusted HR for all-cause mortality among clearly hyperuricaemic individuals with SUA≥420 µmol/L compared with normouricaemic individuals (SUA<360 µmol/L) was 1.32 (95% CI 1.05 to 1.60) in women and 1.29 (95% CI 1.05 to 1.60) in men. In slightly hyperuricaemic individuals (SUA 360-420 µmol/L) the corresponding HRs were 1.03 (95% CI 0.78 to 1.35) and 1.11 (95% CI 0.89 to 1.39).

CONCLUSIONS

Hyperuricaemia is very prevalent in the elderly Finnish population and is independently associated with increased mortality.

Impact of Hyper- and Hypo-Uricemia on Kidney Function

Uric acid (UA) forms monosodium urate (MSU) crystals to exert proinflammatory actions, thus causing gout arthritis, urolithiasis, kidney disease, and cardiovascular disease. UA is also one of the most potent antioxidants that suppresses oxidative stress. Hyper andhypouricemia are caused by genetic mutations or polymorphism. Hyperuricemia increases urinary UA concentration and is frequently associated with urolithiasis, which is augmented by low urinary pH. Renal hypouricemia (RHU) is associated with renal stones by increased level of urinary UA, which correlates with the impaired tubular reabsorption of UA. Hyperuricemia causes gout nephropathy, characterized by renal interstitium and tubular damage because MSU precipitates in the tubules. RHU is also frequently associated with tubular damage with elevated urinary beta2-microglobulin due to increased urinary UA concentration, which is related to impaired tubular UA reabsorption through URAT1. Hyperuricemia could induce renal arteriopathy and reduce renal blood flow, while increasing urinary albumin excretion, which is correlated with plasma xanthine oxidoreductase (XOR) activity. RHU is associated with exercise-induced kidney injury, since low levels of SUA could induce the vasoconstriction of the kidney and the enhanced urinary UA excretion could form intratubular precipitation. A U-shaped association of SUA with organ damage is observed in patients with kidney diseases related to impaired endothelial function. Under hyperuricemia, intracellular UA, MSU crystals, and XOR could reduce NO and activate several proinflammatory signals, impairing endothelial functions. Under hypouricemia, the genetic and pharmacological depletion of UA could impair the NO-dependent and independent endothelial functions, suggesting that RHU and secondary hypouricemia might be a risk factor for the loss of kidney functions. In order to protect kidney functions in hyperuricemic patients, the use of urate lowering agents could be recommended to target SUA below 6 mg/dL. In order to protect the kidney functions in RHU patients, hydration and urinary alkalization may be recommended, and in some cases an XOR inhibitor might be recommended in order to reduce oxidative stress.

Longitudinal uric acid has nonlinear association with kidney failure and mortality in chronic kidney disease

We investigated the shape of the relationship between longitudinal uric acid (UA) and the hazard of kidney failure and death in chronic kidney disease (CKD) patients, and attempted to identify thresholds associated with increased hazards. We included CKD stage 3-5 patients from the CKD-REIN cohort with one serum UA measurement at cohort entry. We used cause-specific multivariate Cox models including a spline function of current values of UA (cUA), estimated from a separate linear mixed model. We followed 2781 patients (66% men, median age, 69 years) for a median of 3.2 years with a median of five longitudinal UA measures per patient. The hazard of kidney failure increased with increasing cUA, with a plateau between 6 and 10 mg/dl and a sharp increase above 11 mg/dl. The hazard of death had a U-shape relationship with cUA, with a hazard twice higher for 3 or 11 mg/dl, compared to 5 mg/dl. In CKD patients, our results indicate that UA above 10 mg/dl is a strong risk marker for kidney failure and death and that low UA levels below 5 mg/dl are associated with death before kidney failure.

Concentration of serum uric acid in patients with Renal Artery Stenosis and Hypertension prEdict Future nephropathy and death: C-RASHEF study

Since both serum uric acid (SUA) and renal artery stenosis (RAS) are associated with atherosclerotic events and renal events, it is interesting to investigate whether SUA could predict long-term outcome in patients with RAS. Patients were enrolled from inpatients from 2010 to 2014, must be ≥40-year-old. There were 3269 hypertensive patients enrolled, including 325 RAS patients. Endpoints included all-cause death and new or worsening nephropathy (NNP). In analysis for all-cause mortality, associations between SUA and risk of all-cause mortality were an arising curve in total population, a U-shape curve in non-RAS population, and an arising curve in RAS population. When RAS was involved in multivariate analysis, association between SUA and risk of all-cause mortality was still an arising curve in total population. In analysis for NNP, associations between SUA and risk of NNP were a declining curve in total population, not significant in non-RAS population, and a U-shape curve in RAS population. When RAS was involved in multivariate analysis, association between SUA and risk of NNP in total population was no longer significant. Not only association curve of SUA with mortality in non-RAS patients is different from association curve in RAS patients, but also association curve of SUA with NNP in non-RAS patients is different from association curve in RAS patients. The authors conclude that mechanisms of uric acid for mortality and NNP in RAS patients are different from non-RAS patients. In addition to renal vascular obstruction, uric acid is another significant factor for NNP and death in RAS patients.

Sex differences between serum uric acid levels and cardiovascular outcomes in patients with coronary artery disease after stent implantation

Background

The relationship between elevated serum uric acid (SUA) levels and cardiovascular outcomes after stent implantation remains uncertain. This study sought to evaluate the impact of SUA on 12-month cardiovascular outcomes after stent implantation.

Methods

We performed a retrospective study of patients who successfully underwent stent implantation and enrolled 3,222 patients with coronary artery disease (CAD) from a single center. SUA levels were measured before stent implantation. The patients were divided into six groups (<4, 4-4.9, 5-5.9, 6-6.9, 7-7.9 and ≥ 8 mg/dL) at SUA intervals of 1.0 mg/dL. The incidence of cardiovascular outcomes in the six groups was monitored for 1 year after stent implantation and the hazard ratios were estimated. Hazard ratios (HRs) and 95% confidence intervals (95% CIs) for cardiovascular outcomes were estimated using a Cox proportional hazard regression analysis. The primary endpoint was all-cause death. The secondary endpoint was a composite of all-cause death, myocardial infarction, target vessel revascularization, stent thrombosis and stroke. The follow-up duration was 12 months.

Results

Over the 12-month follow-up period, there were 101 all-cause deaths and 218 MACCE. After adjustment for several parameters, the group with SUA levels of more than or equal to 8 mg/dL had significantly higher hazard ratios in the incidence of all-cause death or MACCE. The group with <4.0 mg/dL had significantly higher hazard ratios in all-cause death only in male patients. In contrast, there were no significant differences observed for cardiovascular outcomes in female patients.

Conclusions

Our study identified a U-shaped association between SUA levels and cardiovascular outcomes during 12-month follow-up for males, but not for females. Further studies are warranted to clarify the sex differences between SUA levels and clinical outcomes.

Gender-Specific and U-Shaped Relationship Between Serum Uric Acid and All-Cause Mortality Among Chinese Older Adults: A National Population-Based Longitudinal Study

Objectives: This study aimed to prospectively investigate gender-specific relationship between hyperuricemia and all-cause mortality among Chinese older adults. Methods: The study was based on the Chinese Longitudinal Healthy Longevity Survey (CLHLS) 2008-2018, a prospective nationwide cohort of older adults in China. Multivariate Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% CIs for all-cause mortality. Restricted cubic splines (RCS) were conducted to explore the dose-response relationship between SUA levels and all-cause mortality. Results: For older women, compared to the participants in the third quartile of SUA level, those in the highest quartile of SUA was associated with significantly higher risk of all-cause mortality in the fully adjusted model (HR: 1.41, 95% CI: 1.03-1.92). No significant associations between SUA levels and all-cause mortality were observed in older men. The present study further found a U-shaped non-linear relationship between SUA levels and all-cause mortality in both sexes of older population (P for non-linear <0.05). Conclusions: This study provided prospective epidemiological evidence for the predictive role of SUA on all-cause mortality among the Chinese aging population over 10 years of follow-up, while revealing considerable gender-related differences.

Uric acid in metabolic syndrome: Does uric acid have a definitive role?

Increased serum uric acid (SUA) levels are commonly seen in patients with metabolic syndrome and are widely accepted as risk factors for hypertension, gout, non-alcoholic fatty liver disease, chronic kidney disease (CKD), and cardiovascular diseases. Although some ambiguity for the exact role of uric acid (UA) in these diseases is still present, several pathophysiological mechanisms have been identified such as increased oxidative stress, inflammation, and apoptosis. Accumulating evidence in genomics enlightens genetic variabilities and some epigenetic changes that can contribute to hyperuricemia. Here we discuss the role of UA within metabolism and the consequences of asymptomatic hyperuricemia while providing newfound evidence for the associations between UA and gut microbiota and vitamin D. Increased SUA levels and beneficial effects of lowering SUA levels need to be elucidated more to understand its complicated function within different metabolic pathways and set optimal target levels for SUA for reducing risks for metabolic and cardiovascular diseases.

The paradoxical relation between serum uric acid and outcomes of hip fracture in older patients after surgery: A 1-year follow-up study

BACKGROUND

The relation between serum uric acid and bone metabolism has been reported in many studies, but few studies have focused on serum uric acid and fracture rehabilitation. We aimed to explore the potential relationships between serum uric acid and outcomes of hip fractures.

METHODS

A total of 742 patients with hip fractures who underwent surgeries between December 2017 and February 2021 and met the inclusion criteria were included. The data of male and female patients were analyzed separately. Cox models with different adjusted forms were performed to explore the potential risk factors, and restricted cubic splines were used to determine the nonlinear relationships between serum uric acid and outcomes and optimal cutoff points of serum uric acid. Then, the outcomes were analyzed in the groups divided by cutoff points mentioned above, as well as groups divided by the diagnosis of hyperuricemia or gout.

RESULTS

Cox analysis showed that hyperuricemia or gout was associated with increased death risk, and a typical J-shaped curve was observed in the restricted cubic spline. For male patients, a serum uric acid of high level may relate to a high risk of 6-month (P = .008) and 1-year (P = .016) mortality, and a serum uric acid of low level may predict a poor 6-month free walking ability. For female patients, both a serum uric acid of high level and low level were associated with poor 1-year survival (all P < .05), and a serum uric acid of high level may relate to poor 6-month (P = .001) and 1-year (P = .001) free walking ability.

CONCLUSION

Patients with hyperuricemia or gout or patients with high and low levels of serum uric acid may face poor outcomes of hip fractures.

Uric acid and cardiometabolic risk by gender in youth with type 1 diabetes

The aim of this study was to investigate the association between uric acid (UA) and cardiometabolic risk factors (CMRFs) by sex in youth with type 1 diabetes (T1D). Retrospective data collected from 1323 children and adolescents (5–18 years; 716 boys) with T1D recruited in 9 Italian Pediatric Diabetes Centers were analyzed. CMRFs included UA, HbA_1c, blood pressure (BP), cholesterol (TC), HDL, triglycerides (TG), neutrophils (N) and lymphocytes (L) count, glomerular filtration rate (eGFR) (calculated using Schwartz-Lyon equation). In boys, we found a higher age, daily insulin dose, TG, TG/HDL ratio, TC/HDL ratio, systolic BP, N/L ratio and lower HDL, and eGFR across UA tertiles (p = 0.01–0.0001). Similar results were found in girls but not for TG and systolic BP. In boys, the odds ratio (OR) of high levels of TG/HDL ratio, TC/HDL ratio, BP and mildly reduced eGFR (MRGFR) increased for 0.5 mg/dL of UA. Instead, in girls an increased levels of 0.5 mg/dL of UA were associated with high OR of TC/HDL ratio, N/L ratio and MRGFR. Uric acid may represent a useful marker for identifying youth with T1D at high cardiometabolic risk, and this association appears to vary by sex.

The U-Shaped Relationship Between Serum Uric Acid and Long-Term All-Cause Mortality in Coronary Artery Disease Patients: A Cohort Study of 33,034 Patients

Background

Associations between high serum uric acid (SUA) and cardiovascular diseases have been reported. However, few studies have been conducted to explore the relationship between SUA and long-term all-cause mortality in coronary artery disease (CAD) patients. Our study aims to investigate the relationship between SUA and long-term all-cause mortality in patients with CAD.

Methods

From January 2007 to December 2018, we divided 33,034 patients with CAD admitted in the Guangdong Provincial People's Hospital into five groups (quintile 1: SUA <5.05 mg/dl, quintile 2: 5.05 mg/dl ≤ SUA <5.59 mg/dl, quintile 3:5.59 mg/dl ≤ SUA <6.8 mg/dl, quintile 4, 6.8 mg/dl ≤ SUA <7.93 mg/dl, and quintile 5, SUA ≥7.93 mg/d;). This study used Kaplan–Meier survival analysis to evaluate patient outcomes with different ranges of SUA. Cox proportional hazards regression models and restricted cubic spline were applied to determine the association between serum uric and long-term all-cause mortality.

Results

A total of 33,034 participants were recruited, including 24,780 (75.01%) men and 8,254 (24.99) women in this cohort study. Median follow-up was 4.91 years. We found that SUA is an independent risk factor of long-term all-cause mortality according to the result of Cox proportional hazards models. This study also illustrated an approximate U-shape association between SUA and all-cause mortality when compared with 5.95 mg/lL ≤ SUA <6.8 mg/dl, SUA <5.0 5mg/dl (adjusted hazard ratio (aHR) =1.13, 95% CI: 1.01–1.26, p = 0.03), and SUA ≥8 mg/dL (aHR = 1.18, 95% CI: 1.06-1.32, p = 0.003).

Conclusion

Our study indicated a U-shaped relationship between SUA and long-term all-cause mortality in patients with CAD. No matter whether SUA is too high or too low, it increased the all-cause mortality in the CAD population, which deserves to be closely monitored.

High Level of Uric Acid Promotes Atherosclerosis by Targeting NRF2-Mediated Autophagy Dysfunction and Ferroptosis

Atherosclerotic vascular disease (ASVD) is the leading cause of death worldwide. Hyperuricemia is the fourth risk factor for atherosclerosis after hypertension, diabetes, and hyperlipidemia. The mechanism of hyperuricemia affecting the occurrence and development of atherosclerosis has not been fully elucidated. Mononuclear macrophages play critical roles in all stages of atherosclerosis. Studies have confirmed that both hyperuricemia and ferroptosis promote atherosclerosis, but whether high level of uric acid (HUA) promotes atherosclerosis by regulating ferroptosis in macrophages remains unclear. We found that HUA significantly promoted the development of atherosclerotic plaque and downregulated the protein level of the NRF2/SLC7A11/GPX4 signaling pathway in ApoE−/− mice. Next, we evaluated the effect of HUA and ferroptosis inhibitor ferrostatin-1 (Fer-1) treatment on the formation of macrophage-derived foam cells. HUA promoted the formation of foam cells, decreased cell viability, and increased iron accumulation and lipid peroxidation in macrophages treated with oxidized low-density lipoprotein (oxLDL); these effects were reversed by Fer-1 treatment. Mechanistically, HUA significantly inhibited autophagy and the protein level of the NRF2/SLC7A11/GPX4 signaling pathway. Fer-1 activated autophagy and upregulated the level of ferroptosis-associated proteins. Moreover, an NRF2 inducer (tertbutyl hydroquinone (TBHQ)) and autophagy activator (rapamycin (RAPA)) could reverse the inhibitory effect of HUA on foam cell survival. Our results suggest that HUA-induced ferroptosis of macrophages is involved in the formation of atherosclerotic plaques. More importantly, enhancing autophagy and inhibiting ferroptosis by activating NRF2 may alleviate HUA-induced atherosclerosis. These findings might contribute to a deeper understanding of the role of HUA in the pathogenesis of atherosclerosis and provide a therapeutic target for ASVD associated with hyperuricemia.

Effects of genetic and nongenetic factors on hyperuricemia in Chinese patients with coronary artery disease

Aim: The relationship between hyperuricemia and polymorphisms of transporter genes in coronary artery disease (CAD) patients in China remains unclear. Materials & methods: A total of 258 hyperuricemia patients with CAD and 242 control patients with CAD were recruited in this case-control study. Twenty-four SNPs in genes of ABCG2, PDZK1, URAT1, OAT4, GLUT9, ABCC4, NPT1 and NPT4 were genotyped using direct sequencing in all subjects. Results: The mutation of ABCG2 rs2231142 locus increases the risk of hyperuricemia, and there is a gene dose effect in the influence of mutant heterozygotes and homozygotes. rs3825017 in URAT1 and rs62293298 in GLUT9 were also confirmed to be associated with hyperuricemia. Conclusion: Age, weight, creatinine clearance rate, diuretics and SNPs on ABCG2, URAT1 and GLUT9 were all risk factors of hyperuricemia.

U-Shaped Association Between Serum Uric Acid and Short-Term Mortality in Patients With Infective Endocarditis

BACKGROUND

Increased uric acid (UA) levels have been reported to be associated with poor clinical outcomes in several conditions. However, the prognostic value of UA in patients with infective endocarditis (IE) is yet unknown.

METHODS

A total of 1,117 patients with IE were included and divided into two groups according to the current definition of hyperuricemia (UA>420 μmol/L in men and >360 μmol/L in women): hyperuricemia group (n=336) and normouricemia group (n=781). The association between the UA level and short-term outcomes were examined.

RESULTS

The in-hospital mortality was 6.2% (69/1117). Patients with hyperuricemia carried a higher risk of in-hospital death (9.8% vs. 4.6%, p=0.001). Hyperuricemia was not an independent risk factor for in-hospital death (adjusted odds ratio [aOR]=1.92, 95% confidence interval [CI]: 0.92-4.02, p=0.084). A U-shaped relationship was found between the UA level and in-hospital death (p<0.001). The in-hospital mortality was lower in patients with UA in the range 250-400 μmol/L. The aOR of in-hospital death in patients with UA>400 and <250 μmol/L was 3.48 (95% CI: 1.38-8.80, p=0.008) and 3.28 (95%CI: 1.27-8.51, p=0.015), respectively. Furthermore, UA>400 μmol/L (adjusted hazard ratio [aHR]=3.54, 95%CI: 1.77-7.07, p<0.001) and <250 μmol/L (aHR=2.23, 95%CI: 1.03-4.80, p=0.041) were independent risk factors for the 6-month mortality.

CONCLUSION

The previous definition of hyperuricemia was not suitable for risk assessment in patients with IE because of the U-shaped relationship between UA levels and in-hospital death. Low and high levels of UA were predictive of increased short-term mortality in IE patients.